Day: July 9, 2006

Hack-A-Day regular [Andrew] has posted an incredibly simple game port based photogate. He uses a pair of light dependent resistors. Each one is placed inside of a ballpoint pen tube to limit ambient light on the sensor. He’s got a simple QBasic program to calculate the velocity of an object passing the sensors. You’ll have to run it inside a DOS emulator to get access to the game port under XP.